1. Technical Field
The present invention relates to a contact device and a circuit package.
2. Related Art
A conventionally known semiconductor apparatus includes a BGA (Ball Grid Array) type of contact, as shown in, for example, Patent Document 1. Since communication devices are becoming capable of higher-speed communication, data communication between semiconductor integrated circuits within a semiconductor apparatus and external devices is mostly achieved by serial communication using differential signals.
Therefore, a BGA semiconductor apparatus can use a high-speed differential signal as the transmission signal. The following is a list of Patent Documents provided as related art.    Patent Document 1: Japanese Patent Application Publication No. 2006-128633    Patent Document 2: Japanese Patent Application Publication No. 2005-166794    Patent Document 3: Japanese Patent Application Publication No. 2003-249904    Patent Document 4: Japanese Patent Application Publication No. 2003-258510    Patent Document 5: Japanese Patent Application Publication No. 2002-246121
If a plurality of differential pins are arranged with high density on a BGA contact, the differential pins can be arranged on the BGA such that there are no gaps in a prescribed direction. For example, a plurality of contact balls arranged in a straight line can be used to form differential pins, by using two contact balls per differential pin beginning at one end.
However, when the distance between adjacent contact balls is short, it is easy for signal cross talk to occur therebetween. If the differential pins are arranged in a straight line, as described above, each contact ball in a differential pin experiences cross talk from other differential pins.
In order to decrease this cross talk, shield pins can be arranged between each pair of differential pins. However, since the arrangement of contact balls in a BGA is determined in advance, including the shield pins decreases the density with which the differential pins can be arranged.